Measuring signal from photodiode

Thread Starter

Pepe333

Joined Feb 12, 2018
86
Hi all!,
I'm triyng to read a signal from a photodiode in order to read it with a micro.
I see some examples using an OpAmp to amplify the level before input in an ADC.
My question is:
Imagine I have a 5v supply.
¿Why I need to use the OpAmp?
If I put the photodiode with a resitor, like a voltage divider , I can achieve a range from 0 to 5v.
¿Whats the advantage for use an OpAmp?
 
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